Coastal Change During Hurricane Ivan 2004

By Karen L.M. Morgan

Category 3 Hurricane Ivan came ashore near Gulf Shores, Alabama, on September 16, 2004. The barrier islands of the northern Gulf of Mexico near the Florida/Alabama border were exposed to the strongest winds. The communities of Gulf Shores, Pine Island and Orange Beach, AL, are, in places, very low lying with their dunes rising up only several meters. These dunes were unable to contain the 3-4 meter storm surge.

The U.S. Geological Survey (USGS), National Aeronautics and Space Administration (NASA), and U.S. Army Corps of Engineers (USACE) are cooperating in a research project investigating coastal change during Hurricane Ivan. On Friday September 17, 2004, the USGS acquired oblique aerial photography to help understand the impact of Ivan on the coastal environment. Two days later, airborne lidar was collected using NASA Experimental Advanced Airborne Research Lidar (EAARL).

Gulf waters, driven by hurricane force winds spilled across the barrier islands creating currents strong enough to transport massive amounts of sand landward. These waters undermined buildings and roads and opened new island breaches. On top of the surge, breaking waves nearly as tall as the depth of the surge, eroded dunes and battered structures.